


into the waves

by Aceisawesome



Category: Haikyuu!!
Genre: Alternate Universe - Merpeople, M/M, Sirens, Spirited Away - Freeform, slight mention of blood and siren-induced madness, vanishing into the ocean the way I've always dreamed of
Language: English
Status: Completed
Published: 2021-01-25
Updated: 2021-01-25
Packaged: 2021-03-18 04:42:38
Rating: Teen And Up Audiences
Warnings: No Archive Warnings Apply
Chapters: 1
Words: 1,758
Publisher: archiveofourown.org
Story URL: https://archiveofourown.org/works/28986558
Author URL: https://archiveofourown.org/users/Aceisawesome/pseuds/Aceisawesome
Summary: Kiyoomi had grown up on a small town on the coast, with tales of the sea and warnings of the dangerous creatures within. He knew the rules; always let someone know where you’re going, never approach the shore alone, and most importantly: if you start to hear singing, block your ears and leave immediately.It was unfortunate that he broke every one of those rules the day he spotted something gold at sea, glittering among the waves in the setting sun.
Relationships: Miya Atsumu/Sakusa Kiyoomi
Comments: 1
Kudos: 47





	into the waves

Kiyoomi had grown up on a small town on the coast, with tales of the sea and warnings of the dangerous creatures within. He knew the rules; always let someone know where you’re going, never approach the shore alone, and most importantly: if you start to hear singing, block your ears and leave immediately.

It was unfortunate that he broke every one of those rules the day he spotted something gold at sea, glittering among the waves in the setting sun.

* * *

He’d been angry about- something, frustrated enough to leave without a word to Motoya and go where he knew no one else would be. The salty sea breeze cooled his temper as the solitude of the rocky shore calmed him down, and in that moment he could imagine he was the only person in the world.

  
The illusion was broken when a faint sound tickled his hearing, making him look around for its source. He could see no one, but something unusual stuck out: a glimmer of gold at sea, too stationary to be the reflection of the sun in waves. With a furrowed brow, Kiyoomi stepped off the wooden path onto the sand, wrinkling his nose at the thought of having to shake it out of his shoes later, but too intrigued about the gold to ignore it.

  
His reservations faded as he moved closer to the water’s edge and the sound grew clearer, recognisable as a melodious hum. He could see the golden glint slowly bobbing on the waves, faint ripples appearing from beyond it, from something that only surfaced occasionally but still glittered in the setting sun. Kiyoomi now identified the gold as a head of hair, but that realisation only brought more questions with it. Someone sunbathing? In the water? Alone, at this hour? Who on earth could it be?

  
The humming anchored his feet to the sand, some wordless tune that felt both familiar and something completely new. He stayed for what felt like hours, staring into the slowly darkening sea, water starting to lap at his shoes, until he heard a faint “Kiyoomi!” in the distance; Motoya had come looking for him. He didn’t look back, however: the sound had alerted whoever was out there, and they had turned around to look at Kiyoomi.

  
The world could have fallen apart under his feet and he wouldn’t have noticed. From the distance, it was hard to see many details of the person’s face, but the eyes were clear as the sun behind them as they pierced through Kiyoomi. Bright and golden and gone too soon, as the person – was it a person? – dived under the waves, a flicker of dark scales leaving behind a series of ripples, the only indication that someone had been there in the first place.

Kiyoomi took a heaving breath of salty air, and it felt like his very first.

* * *

The following weeks were maddening. After avoiding his cousin’s questions, Kiyoomi tried to forget the whole encounter happened. He knew clearly that what he’d seen was dangerous, something that he’d been warned against his entire life. The webbed protrusions he’d seen in place of the person’s ears, the scaled tail he now realised had been keeping them afloat; he’d seen a siren, and fallen under its spell, and the only reason he hadn’t drowned himself in a frenzy to reach it was that it hadn’t been looking to feed. He was lucky to still be alive, and should move on with his life.

It was easier said than done.

Every time he closed his eyes, he could feel those golden eyes piercing through him, and craved to see them again. Every time the sun set, he remembered the golden glint that had captured his attention in the first place, and more than once he caught himself heading to the shore without meaning to. The pitying gazes of the older fishermen when he looked too often to sea frustrated him to no end; they saw him and shook their heads sadly, like they’d seen this happen before, like he was already doomed.

  
It didn’t help that he could still spot gold among the waves sometimes, disappearing in the next instant, when he looked at the sea from afar on his way to work. Too quick to be certain, but too often to be imagined (he hoped).

* * *

He ended up at the beach again at the end of the month, leaving his shoes behind on the wooden path. The water lapped at his feet, cool and red in the setting sun, but Kiyoomi could barely feel it, too focused on scouring the sea. He was fed up with the constant distraction to his daily life, and had decided to do something about it.

  
It wasn’t long before he felt a prickling on his skin, distinct from the sea breeze; someone’s gaze, burning into him. With newfound desperation, he took a step forwards and-

  
There, under the water, just a few meters ahead: golden strands floating around piercing gold eyes, a fascinated gaze looking up at him. A second passed when their eyes met, and the siren smirked and turned away. A black tail shone in the water.

  
Before he even realised it, Kiyoomi was running into the sea, chasing that tail.

* * *

He caught up to the siren surprisingly fast, water still around his waist as he lunged at the pale torso. The siren barely put up a resistance, simply twisting around and looking up at Kiyoomi, eyes wide in pure admiration. The sight, tinted red from sunset, was maddening. Feeling almost manic, he dragged the siren to the surface.

  
“What have you done to me?!” Kiyoomi snarled, grabbing the sides of its head, just under the webbed protrusions. It only grinned, exposing razor-sharp fangs.

  
“What do you mean?” Such a velvety voice, contrasting those teeth so delightfully, making his head spin and crave more.

  
“You’re in my mind, constantly, and everything I do to make it stop just makes me think of you more,” he hissed through gritted teeth.

  
“And?” A cold hand wrapped around one of Kiyoomi’s, the siren leaning into it, entrancing golden eyes narrowing just a little. Delighted. “What will you do about it?”

  
A growl escaped Kiyoomi before he pressed his lips to the siren’s, uncaring of the cold, the water creeping up his chest, the sharp fangs he’d seen before. Blood flowed near immediately, the metallic taste mixing with salt until it was all Kiyoomi could taste. He was dizzy, drowning in the siren’s mouth. He wanted more.

  
The siren pulled back with a moan and a laugh as Kiyoomi leaned forwards, chasing his lips. The water was up to his shoulders now, and he could feel something smooth brushing against his legs as he kept moving forwards, losing his footing on the seafloor as he went.

  
Clawed hands gently pushed at his shoulders, bringing them both to a stop. The siren’s eyes shone even brighter in the darkening evening, the sun having already set. A smile still played on his lips, but his eyes were serious as he faced Kiyoomi.

  
“You won’t be able to go back if you keep going. Are you sure?”

  
And suddenly, Kiyoomi’s head was clearer than it had been in a month. The siren was giving him a choice; to go back to land, to his family, to his life, or vanish into the sea, never to be seen again.  
He looked up. The siren was watching him silently, awaiting his answer.

  
“Why? You could have eaten me by now, but you’re letting me go? I… don’t understand.”

  
The siren smiled slightly. “I could have indeed. But I never planned to eat you, pretty human. What I’m offering requires a choice, if you’re willing to take it.”

  
The black tail brushed against Kiyoomi’s legs again, purposefully, and he fully understood. None of the tales had mentioned this possibility, but that was likely because none who had been offered this choice refused it. Kiyoomi, looking into the siren’s mesmerising eyes, knew he wasn’t about to be the first.

  
The question still burned on his tongue. “Why me?”

  
Those golden eyes softened, melting. “For the same reason you came tonight. The same reason why I’ve stayed here after being seen, returned to this beach so many times. I want to know you, human, and I think you do too.”

  
Kiyoomi huffed. “Awfully confident I’ll say yes, aren’t you?” At the answering smirk, he added, “It’s Kiyoomi. You won’t be able to call me human for much longer, I believe.” He stepped forwards.

  
He’d come this far, chasing this siren’s call. He would see it through to the end. The blinding grin, making that golden face shine brighter than the rising moon, felt like coming home.

  
“I’m Atsumu. Glad to hear that, Omi-omi!” Ignoring the grumble at the nickname, he grabbed Kiyoomi’s hands and led him further into the dark sea.

* * *

In the morning, a pair of abandoned shoes and the tattered remains of clothes were all that was found of Sakusa Kiyoomi. There was a small uproar at the disappearance, but not as big as it would be in other towns; after all, many had seen or heard of his erratic behaviour prior to the event, with news of a potential siren victim spreading quickly. One fisherman confirmed it: the day before disappearing, Sakusa had headed down the beach with vacant eyes, not reacting to greetings nor warnings, too far gone to hear anything other than the sea. A tragic event, to be moved on from and added to children’s stories as further warning.

  
If, every year, Komori Motoya spotted a pair of scaled bodies lingering near the shore, he mentioned it to no one. If the sight of his cousin’s face, coupled with an electric yellow tail that contrasted the siren beside him near perfectly, filled him with relief, he kept it to himself.

  
He never went out to talk to them; the allure of the sea could prove too strong for him as well, and someone had to take care of those Kiyoomi had left behind. Still, every year, he made sure to stay at the beach until he saw two heads surface, one shining gold, the other gleaming black.

  
It didn’t need to be a long reunion; a look from afar, a nod and a smile, before he dusted off the sand from himself and the pair sank back underneath the waves. Enough to know the other was alive and well, before they returned to their respective homes.

**Author's Note:**

> Finally wrote a mer fic!!! I love mermaids and the ocean, and eagerly await the day my hot mermaid gf will bring me to live where light doesn't reach. In the meanwhile, writing fic about it will have to do lmao
> 
> Atsumu is naturally blond in this bc exotic mermaid colourings. Enjoy the contrast of atsumu with the sleek black tail and kiyoomi with the neon yellow one~
> 
> Let me know if you feel any tags should be added to the fic! Hope you enjoyed!!


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